title: Salt-assisted direct exfoliation of graphite into high-quality, large-size, few-layer graphene sheets.
abstract: We report a facile and low-cost method to directly exfoliate graphite powders into large-size, high-quality, and solution-dispersible few-layer graphene sheets. In this method, aqueous mixtures of graphite and inorganic salts such as NaCl and CuCl2 are stirred, and subsequently dried by evaporation. Finally, the mixture powders are dispersed into an orthogonal organic solvent solution of the salt by low-power and short-time ultrasonication, which exfoliates graphite into few-layer graphene sheets. We find that the as-made graphene sheets contain little oxygen, and 86% of them are 1-5 layers with lateral sizes as large as 210 μm(2). Importantly, the as-made graphene can be readily dispersed into aqueous solution in the presence of surfactant and thus is compatible with various solution-processing techniques towards graphene-based thin film devices.
authors.affiliation: Nanotechnology Center, Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hong Kong SAR, China.
authors.forename: Liyong
authors.initials: L
authors.lastname: Niu
authors.forename: Mingjian
authors.initials: M
authors.lastname: Li
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Tao
authors.forename: Zhuang
authors.initials: Z
authors.lastname: Xie
authors.forename: Xuechang
authors.initials: X
authors.lastname: Zhou
authors.forename: Arun P A
authors.initials: AP
authors.lastname: Raju
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Young
authors.forename: Zijian
authors.initials: Z
authors.lastname: Zheng
mesh_terms: D003300:Copper / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry*; D010316:Particle Size; D012965:Sodium Chloride / Q000737:chemistry; D013010:Sonication
chemical_list: D012965:Sodium Chloride; D006108:Graphite; D003300:Copper; C029892:cupric chloride